Multiparametric Cardiac Magnetic Resonance Imaging Can Detect Acute Cardiac Allograft Rejection After Heart Transplantation

Dolan, Ryan S.; Rahsepar, Amir Ali; Blaisdell, Julie; Suwa, Kenichiro; Ghafourian, Kambiz; Wilcox, Jane E.; Khan, Sadiya S.; Vorovich, Esther; Rich, Jonathan D.; Anderson, Allen S.; Yancy, Clyde W.; Collins, Jeremy D.; Carr, James C.; Markl, Michael

doi:10.1016/j.jcmg.2019.01.026

Cited by 71 publications

(60 citation statements)

References 32 publications

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“…This may suggest that in this cohort higher T2 values reflect myocardial fibrosis, similar to results using T1 mapping techniques. Recently published data in a similar cohort of patients found elevation of T2 and T1 values in all transplanted patients, even without history of cardiac rejection, and the authors suggest this is due to greater myocardial oedema and interstitial fibrosis at baseline 23. However, we contend that elevated T2 in the myocardium of cardiac allografts in this cohort may reflect intrinsic changes to the cellular architecture, such as the presence of myocardial fibrosis and not myocardial oedema.…”

Section: Discussionsupporting

confidence: 52%

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

et al. 2019

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ObjectivesUltra-small superparamagnetic particles of iron oxide (USPIO)-enhanced MRI can detect cellular inflammation within tissues and may help non-invasively identify cardiac transplant rejection. Here, we aimed to determine the normal reference values for USPIO-enhanced MRI in patients with a prior cardiac transplant and examine whether USPIO-enhanced MRI could detect myocardial inflammation in patients with transplant rejection.MethodsTen volunteers and 11 patients with cardiac transplant underwent T2, T2* and late gadolinium enhancement 1.5T MRI, with further T2* imaging at 24 hours after USPIO (ferumoxytol, 4 mg/kg) infusion, at baseline and 3 months.ResultsTen patients with clinically stable cardiac transplantation were retained for analysis. Myocardial T2 values were higher in patients with cardiac transplant versus healthy volunteers (53.8±5.2 vs 48.6±1.9 ms, respectively; p=0.003). There were no differences in the magnitude of USPIO-induced change in R2* in patients with transplantation (change in R2*, 26.6±7.3 vs 22.0±10.4 s-1 in healthy volunteers; p=0.28). After 3 months, patients with transplantation (n=5) had unaltered T2 values (52.7±2.8 vs 52.12±3.4 ms; p=0.80) and changes in R2* following USPIO (29.42±8.14 vs 25.8±7.8 s-1; p=0.43).ConclusionStable patients with cardiac transplantation have increased myocardial T2 values, consistent with resting myocardial oedema or fibrosis. In contrast, USPIO-enhanced MRI is normal and stable over time suggesting the absence of chronic macrophage-driven cellular inflammation. It remains to be determined whether USPIO-enhanced MRI may be able to identify acute cardiac transplant rejection.Trial registration numberNCT02319278349 (https://clinicaltrials.gov/ct2/show/NCT02319278) Registered 03.12.2014 EUDraCT 2013-002336-24.

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Section: Discussionsupporting

confidence: 52%

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

et al. 2019

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“…Importantly, T 2 is well known to characterize a plethora of important disease processes such as iron deposition, fibrosis, edema, malignancy, and inflammation, among others. As a result, quantitative T 2 mapping with MRI has many applications, including assessment of neuro‐degenerative diseases and characterization of malignant lesions, detection of myocardial edema, detection of chronic rejection after heart transplant, detection of early cartilage degeneration, quantification of liver iron overload, and even identification of myofascial trigger points …”

Section: Introductionmentioning

confidence: 99%

Phase‐based T₂mapping with gradient echo imaging

Wang

Hernando

Reeder

2019

Magnetic Resonance in Med

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Purpose: Transverse relaxation time (T 2 ) mapping with MRI has a plethora of clinical and research applications. Current T 2 mapping techniques are based primarily on spin-echo (SE) relaxometry strategies that rely on the signal magnitude, and often suffer from lengthy acquisition times. In this work, we propose a phase-based T 2 mapping technique where T 2 information is encoded into the signal phase of rapid gradient echo (GRE) acquisitions. Theory: Bloch equation simulations demonstrate that the phase of GRE acquisitions obtained with a very small inter-repetition RF phase increment has a strong monotonic dependence on T 2 , resulting from coherent transverse magnetization. This T 2 -dependent phase behavior forms the basis of the proposed T 2 mapping technique.To isolate T 2 -dependent phase from background phase, at least 2 data sets with different RF phase increments are acquired. The proposed method can also be combined with chemical shift encoded MRI to separate water and fat signals. Methods: The feasibility of the proposed technique was validated in a phantom experiment. In vivo feasibility was demonstrated in the brain, knee, abdomen, and pelvis. Comparisons were made with SE-based T 2 mapping, spectroscopy, and T 2 values from the literature. Results:The proposed method produced accurate T 2 maps compared with SE-based T 2 mapping in the phantom. Good qualitative agreement was observed in vivo between the proposed method and the reference. T 2 measured in various anatomies agreed well with values reported in the literature. Conclusion: A phase-based T 2 mapping technique was developed and its feasibility demonstrated in phantoms and in vivo. K E Y W O R D S gradient echo, magnetic resonance imaging, phase, quantitative imaging biomarker, relaxometry, RF spoiling, T 2 mapping 610 | WANG et Al.How to cite this article: Wang X, Hernando D, Reeder SB. Phase-based T 2 mapping with gradient echo imaging. Magn Reson Med. 2020;84:609-619.

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“…Because our study aimed to investigate the utility of T2 values as a possible biomarker for rejection, we considered each patient encounter as an independent study case regardless of the patient's prior history of rejection. There is a large body of evidence, both animal and human studies, demonstrating the association of graft rejection with an increase in T2 time from baseline, suggesting that T2 reproducibly increases in response to acute graft rejection 9,15,19,[36][37][38] . In addition, in sequential studies, the prolonged T2 time returns to baseline after the episode of rejection resolves.…”

Section: Discussionmentioning

confidence: 99%

“…Each T1 and T2 mean value in the septal and lateral positions in the short-axis and four-chamber slices were averaged to generate an overall mean T1 and T2 value for each study, similar to work from other groups. 15,19 T1 reference values are locally maintained per our institution's lab standard. T2 reference values are derived from prior published work.…”

Section: Parametric Map Analysismentioning

confidence: 99%

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Quantitative cardiac magnetic resonance T2 imaging offers ability to non-invasively predict acute allograft rejection in children

Sethi

Doshi

et al. 2020

Cardiol Young

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Background:Monitoring for acute allograft rejection improves outcomes after cardiac transplantation. Endomyocardial biopsy is the gold standard test defining rejection, but carries risk and has limitations. Cardiac magnetic resonance T2 mapping may be able to predict rejection in adults, but has not been studied in children. Our aim was to evaluate T2 mapping in identifying paediatric cardiac transplant patients with acute rejection.Methods:Eleven paediatric transplant patients presenting 18 times were prospectively enrolled for non-contrast cardiac magnetic resonance at 1.5 T followed by endomyocardial biopsy. Imaging included volumetry, flow, and T2 mapping. Regions of interest were manually selected on the T2 maps using the middle-third technique in the left ventricular septal and lateral wall in a short-axis and four-chamber slice. Mean and maximum T2 values were compared with Student’s t-tests analysis.Results:Five cases of acute rejection were identified in three patients, including two cases of grade 2R on biopsy and three cases of negative biopsy treated for clinical symptoms attributed to rejection (new arrhythmia, decreased exercise capacity). A monotonic trend between increasing T2 values and higher biopsy grades was observed: grade 0R T2 53.4 ± 3 ms, grade 1R T2 54.5 ms ± 3 ms, grade 2R T2 61.3 ± 1 ms. The five rejection cases had significantly higher mean T2 values compared to cases without rejection (58.3 ± 4 ms versus 53 ± 2 ms, p = 0.001).Conclusions:Cardiac magnetic resonance with quantitative T2 mapping may offer a non-invasive method for screening paediatric cardiac transplant patients for acute allograft rejection. More data are needed to understand the relationship between T2 and rejection in children.

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Multiparametric Cardiac Magnetic Resonance Imaging Can Detect Acute Cardiac Allograft Rejection After Heart Transplantation

Cited by 71 publications

References 32 publications

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

Phase‐based T₂mapping with gradient echo imaging

Quantitative cardiac magnetic resonance T2 imaging offers ability to non-invasively predict acute allograft rejection in children

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Multiparametric Cardiac Magnetic Resonance Imaging Can Detect Acute Cardiac Allograft Rejection After Heart Transplantation

Cited by 71 publications

References 32 publications

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

Ferumoxytol-enhanced MRI in patients with prior cardiac transplantation

Phase‐based T2mapping with gradient echo imaging

Quantitative cardiac magnetic resonance T2 imaging offers ability to non-invasively predict acute allograft rejection in children

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Phase‐based T₂mapping with gradient echo imaging